Quenched lattice fluctuations in optically driven SrTiO3

Crystal lattice fluctuations, which are known to influence phase transitions of quantum materials in equilibrium, are also expected to determine the dynamics of light-induced phase changes. However, they have only rarely been explored in these dynamical settings. Here we study the time evolution of lattice fluctuations in the quantum paraelectric SrTiO3, in which mid-infrared drives have been shown to induce a metastable ferroelectric state. Crucial in these physics is the competition between polar instabilities and antiferrodistortive rotations, which in equilibrium frustrate the formation of long-range ferroelectricity. We make use of high-intensity mid-infrared optical pulses to resonantly drive the Ti-O-stretching mode at 17 THz, and we measure the resulting change in lattice fluctuations using time-resolved X-ray diffuse scattering at a free-electron laser. After a prompt increase, we observe a long-lived quench in R-point antiferrodistortive lattice fluctuations. Their enhancement and reduction are theoretically explained by considering the fourth-order nonlinear phononic interactions to the driven optical phonon and third-order coupling to lattice strain, respectively. These observations provide a number of testable hypotheses for the physics of light-induced ferroelectricity.

Ultrafast Suppression of the Ferroelectric Instability in KTaO_{3}

We use an x-ray free-electron laser to study the lattice dynamics following photoexcitation with ultrafast near-UV light (wavelength 266 nm, 50 fs pulse duration) of the incipient ferroelectric potassium tantalate, KTaO_{3}. By probing the lattice dynamics corresponding to multiple Brillouin zones through the x-ray diffuse scattering with pulses from the Linac Coherent Light Source (LCLS) (wavelength 1.3 Å and <10  fs pulse duration), we observe changes in the diffuse intensity associated with a hardening of the transverse acoustic phonon branches along Γ to X and Γ to M. Using force constants from density functional theory, we fit the quasiequilibrium intensity and obtain the instantaneous lattice temperature and density of photoexcited charge carriers. The density functional theory calculations demonstrate that photoexcitation transfers charge from oxygen 2p derived π-bonding orbitals to Ta 5d derived antibonding orbitals, further suppressing the ferroelectric instability and increasing the stability of the cubic, paraelectric structure.

Direct Observation of Coherent Longitudinal and Shear Acoustic Phonons in TaAs Using Ultrafast X-Ray Diffraction

Using femtosecond time-resolved x-ray diffraction, we investigated optically excited coherent acoustic phonons in the Weyl semimetal TaAs. The low symmetry of the (112) surface probed in our experiment enables the simultaneous excitation of longitudinal and shear acoustic modes, whose dispersion closely matches our simulations. We observed an asymmetry in the spectral line shape of the longitudinal mode that is notably absent from the shear mode, suggesting a time-dependent frequency chirp that is likely driven by photoinduced carrier diffusion. We argue on the basis of symmetry that these acoustic deformations can transiently alter the electronic structure near the Weyl points and support this with model calculations. Our study underscores the benefit of using off-axis crystal orientations when optically exciting acoustic deformations in topological semimetals, allowing one to transiently change their crystal and electronic structures.

Observation of photo-induced plasmon-phonon coupling in PbTe via ultrafast x-ray scattering

We report the observation of photo-induced plasmon-phonon coupled modes in the group IV-VI semiconductor PbTe using ultrafast x-ray diffuse scattering at the Linac Coherent Light Source. We measure the near-zone-center excited-state dispersion of the heavily screened longitudinal optical (LO) phonon branch as extracted from differential changes in x-ray diffuse scattering intensity following above bandgap photoexcitation. We suggest that upon photoexcitation, the LO phonon-plasmon coupled (LOPC) modes themselves become coupled to longitudinal acoustic modes that drive electron band shifts via acoustic deformation potentials and possibly to low-energy single-particle excitations within the plasma and that these couplings give rise to displacement-correlations that oscillate in time with a period given effectively by the heavily screened LOPC frequency.

Photocurrent-driven transient symmetry breaking in the Weyl semimetal TaAs

Symmetry plays a central role in conventional and topological phases of matter, making the ability to optically drive symmetry changes a critical step in developing future technologies that rely on such control. Topological materials, like topological semimetals, are particularly sensitive to a breaking or restoring of time-reversal and crystalline symmetries, which affect both bulk and surface electronic states. While previous studies have focused on controlling symmetry via coupling to the crystal lattice, we demonstrate here an all-electronic mechanism based on photocurrent generation. Using second harmonic generation spectroscopy as a sensitive probe of symmetry changes, we observe an ultrafast breaking of time-reversal and spatial symmetries following femtosecond optical excitation in the prototypical type-I Weyl semimetal TaAs. Our results show that optically driven photocurrents can be tailored to explicitly break electronic symmetry in a generic fashion, opening up the possibility of driving phase transitions between symmetry-protected states on ultrafast timescales.

Postpartum depression: How it differs from the “baby blues”

Introduction

Despite many signs and symptoms of depression get dismissed as normal physiologic changes associated with childbirth, depressive disorders are a common complication of pregnancy and postpartum period. The so-called “baby blues” have a minor functional impact and respond well to social support, whilst postpartum depression causes significant functional compromise, requiring more aggressive therapy. There is an extreme type of postpartum depressive disorder, postpartum psychosis, when patients present psychosis, mania, or thoughts of infanticide. It is imperative to promptly recognize and differentiate these entities, in order to minimize its impact on both mother and child. Antidepressant treatment may be necessary for some women, but risks and benefits should always be considered prior to institute pharmacotherapy.

Objectives

To identify current approaches and evidence-based treatment options for postpartum depression.

Methods

Review of the most recent literature regarding postpartum depression. The research was carried out through the Cochrane, UptoDate, PubMed, MedLine, LILACS and SciELO databases, using the terms “postpartum depression”, “baby blues” and “postpartum psychosis”, until December 2020.

Results

Since both depression and antidepressant medications confer risk upon the infant, when postpartum depression develops, psychotherapy is usually the first-line treatment. Antidepressant treatment may be necessary, but its use during pregnancy and postpartum must be weighed carefully.

Conclusions

In order to better prevent postpartum depression, recommendations include the use of screening instruments as a routine clinical practice during pregnancy and referral when necessary. Maternal depression has a severe impact on both mother and child, so mental health professionals have a very important role in reducing postnatal emotional complications.

Disclosure

No significant relationships.

Internet addiction disorder: When technology becomes a problem

Introduction

Internet addiction disorder (IAD) is the compulsive and problematic use of the internet, resulting in significant functional impairment in several life domains. This happens when an individual engages in online activities disregarding daily responsibilities or other interests, and not realizing its negative consequences. Although not officially recognized as a disorder in the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-V), the relationships between digital media use and mental health has been under debate and discussion amongst experts due to presenting some features of excessive use, withdrawal phenomena, tolerance, and negative repercussions typical of many substance abuse disorders.

Objectives

To present an overview of theoretical considerations on IAD and its eventual inclusion in the next version of the DSM.

Methods

Review of the most recent literature regarding internet addiction disorder. The research was carried out through the PubMed, MedLine, SpringerLink and LILACS databases, using the terms “internet addiction”, “addiction disorders” and “social media”, until December 2020.

Results

There is controversy around the diagnosis of internet addiction, including whether it is a unique clinical entity or a manifestation of other underlying psychiatric disorders, raising complex questions of causality. Since there are no standardized definition, there is lack of evidence-based recommendations to its approach.

Conclusions

Research suggests that some individuals dealing with internet addiction are at significant risk, therefore merit professional care. Further research is needed, with carefully controlled studies, emphasizing incapacity, prognosis and response to treatment, in order to consider internet addiction as a disease, and include it in DSM’s next edition.

Disclosure

No significant relationships.

Therapeutic use of psychedelic drugs in depression disorders

Introduction

Depression is one of the most prevalent mental illnesses, leading to important personal distress and economic consequences. Treatment is long, often involving psychotherapy and pharmacological treatment, and relapses are frequent. Used mostly for treatment of mood disorders and alcohol dependence, drugs such as lysergic acid diethylamide (LSD) were studied in the 1950’s and showed therapeutic promise in attenuating depressive symptoms. However, in the 1960s all major psychedelic research programs were ended. Recently, there is a renewed research interest in these drugs, considering its antidepressant potential.

Objectives

To review current knowledge on the therapeutic uses of psychedelic drugs such as LSD in depression disorders.

Methods

Review of the most recent literature regarding the therapeutical potential of psychedelic drugs such as LSD in depression disorders. The research was carried out through the UptoDate, PubMed, MedLine, ScienceDirect and SpringerLink databases, using the terms “LSD”, “psychedelic drugs” and “depression disorders”, until December 2020.

Results

As in past scientific studies, data of recent clinical research shows that the use of LSD relieves distress concerning death, particularly in terminally ill oncologic patients, and addictions including alcoholism and nicotine. There is more limited data concerning the use of classic hallucinogens to treat depression and anxiety disorders.

Conclusions

Although research has shown many of the neurobiological and psychological effects of classic hallucinogens on humans, the studies that have been completed to date are not sufficient to establish clinically relevant effects. Despite further research is needed, the outcomes are encouraging, and larger, well-designed, placebo-controlled trials are now underway or being planned.

Disclosure

No significant relationships.

The role of the gut-brain axis in depression and anxiety disorders

Introduction

There is a bi-directional biochemical communication pathway between the gastrointestinal tract and the central nervous system, referred to as the “gut–brain axis”. Studies show that bacteria in the gastrointestinal tract, including commensal, probiotic, or pathogenic, can affect brain’s function. Since there is a symbiotic relationship between gut microbiota and the brain, changes in its composition can lead to dysbiosis, which plays a role in many psychiatric disorders, such as depression and anxiety, and therefore becomes a potential therapeutic target.

Objectives

To examine data from recent studies regarding the gut-brain axis and its relationship with psychiatric disorders, such as depression and anxiety.

Methods

Review of the most recent literature regarding the gut-brain axis and its relationship with depression and anxiety disorders. The research was carried out through the MedLine, PubMed, UptoDate, ScienceDirect, SciELO and SpringerLink databases, using the terms “gut-brain axis”, “depression” and “anxiety”, until December 2020.

Results

There is a relationship between dysbiosis of microbiota and some psychiatric disorders, particularly depression. Symbiosis may be restored by purposefully manipulate the gut microbiota using therapies such as probiotics, therefore enhancing beneficial bacteria in the gastrointestinal tract and improving symptoms of depression.

Conclusions

Although probiotics can be used in the treatment of depression, further research is needed in order to carefully determine parameters such as the duration of treatment, dosage and drug interactions. Nonetheless, a better understanding of the gut-brain axis may arise new approaches on how we prevent and treat mental illnesses.

Disclosure

No significant relationships.

Co-use of tobacco and cannabis: Complicated partnerships

Introduction

Treating addiction is more challenging when there are co-addictions. Tobacco smoking is commonly associated with substance abuse, alcohol use disorders, excessive caffeine intake and pathological gambling among other addictions. Smoking reduction and cessation programmes´ objectives benefit from interventions targeting co-addictions.

Objectives

Difficulties arising from smoking reduction and cessation in the context of co-use of cannabis prompt literature review and reflection of a smoking cessation programme team.

Methods

Pubmed and Google Scholar literature search using terms smoking cessation / tobacco cessation and cannabis.

Results

Co-use of tobacco and cannabis is: 1) very common, 2) associated with greater prevalence of morbidity and social problems, 3) associated with greater dependence of the other substances, 4) negatively influences quit outcomes of either, 5) increases the risk of relapse. Co-users are more likely to perceive the harmful effects of tobacco, have greater motivation and are more likely to quit tobacco than cannabis, which may be perceived as low risk. Treatment of either tobacco smoking or cannabis use may lead to compensatory increase in use of the other substance. There is a significant lack of literature on co-use treatment strategies.

Conclusions

Co-use of tobacco and cannabis makes cessation and relapse prevention of either addiction more difficult and should be taken into account in smoking reduction and cessation programmes and in cannabis treatment interventions. Treatment targetting both tobacco and cannabis use, either simultaneously or sequentially, is likely more successful than interventions targeting only either one. Much remais to be studied on how to treat co-use of tobacco and cannabis.

Psychiatric aspects of the end of life in oncologic patients

Introduction

Patients with life-limiting oncologic conditions should be approached by multidisciplinary teams that contribute to improve their quality of life, including support from mental health dedicated professionals. It is the role of the psychiatrist to understand the relationship between mental health and general health outcomes, specific of this type of patients. Terminally ill and dying patients benefit from psychiatric support, and it seems to have real effects in terms of patient care and medical staff education.

Objectives

To identify approaches and mental health professionals’ practices regarding end-of-life issues in terminally ill cancer patients.

Methods

Review of the most recent literature regarding end-of-life issues in terminally ill cancer patients. The research was carried out through the Cochrane, UptoDate, PubMed, MedLine, LILACS and SciELO databases, using the terms “oncology”, “psychiatry” and “end of life”, until December 2020.

Results

While symptoms of anxiety and depression are common in palliative care settings, generally related to feelings of helplessness and fear of death, they should not be assumed to be an inevitable part of it. For terminally ill patients, anxiety and trauma-related disorders can manifest in various ways and it is important to establish personalized treatment approaches, based on a supportive clinical team, and, if necessary, psychotherapy and psychopharmacologic or complementary treatments.

Conclusions

It is extremely important to assess terminally ill patients from the mental health point of view. It is required that psychiatrists take part in clinical care and research on the treatment of these patients with severe medical conditions, in order to increase their quality of life.

Disclosure

No significant relationships.

The impact of protective face masks and coverings on patient-health provider communication

Introduction

Amid the COVID-19 pandemic the trend points to universal use of protective face masks. The impact posed on verbal and non-verbal communication by masks is yet another challenge to be addressed in clinical care.

Objectives

To reflect on the consequences of face mask and covering use on communication in the clinical setting, including mental health settings.

Methods

Pubmed and Google Scholar literature search using terms face mask / face covering and communication / emotion.

Results

There is a lack of literature on the impact of protective face masks and coverings on communication in clinical settings. Face masks and coverings may have a significant impact on patient-healthcare professional relationship due to disruption of verbal (poorer quality of speech transmission) and non-verbal communication (emotional expression and recognition) with consequences on: 1) clarity of communication with potential for misunderstanding clinical information, advice and prescriptions posing safety issues, 2) emotion perception, expression and reciprocity, 4) perception of healthcare professionals’ empathy and therefore, 3) patient satisfaction, 4) quality of care, and 5) clinical outcomes. Difficulties in communication between the patients´family or other carers and healthcare providers and between healthcare professionals are likewise challenged. People with hearing impairment, children and people with mental illness may be especially vulnerable to these difficulties in communication.

Conclusions

Protective face masks and coverings are undoubtedly important in preventing spread of COVID-19, nonetheless mental healthcare professionals should take into account their significant impact on verbal and non-verbal communication in clinical care. Alternative strategies to enhance communication and rapport may be warranted.

Clinical experience with integrase inhibitors in HIV-2-infected individuals in Spain

BACKGROUND

HIV-2 is a neglected virus despite estimates of 1-2 million people being infected worldwide. The virus is naturally resistant to some antiretrovirals used to treat HIV-1 and therapeutic options are limited for patients with HIV-2.

METHODS

In this retrospective observational study, we analysed all HIV-2-infected individuals treated with integrase strand transfer inhibitors (INSTIs) recorded in the Spanish HIV-2 cohort. Demographics, treatment modalities, laboratory values, quantitative HIV-2 RNA and CD4 counts as well as drug resistance were analysed.

RESULTS

From a total of 354 HIV-2-infected patients recruited by the Spanish HIV-2 cohort as of December 2017, INSTIs had been given to 44, in 18 as first-line therapy and in 26 after failing other antiretroviral regimens. After a median follow-up of 13 months of INSTI-based therapy, undetectable viraemia for HIV-2 was achieved in 89% of treatment-naive and in 65.4% of treatment-experienced patients. In parallel, CD4 gains were 82 and 126 cells/mm3, respectively. Treatment failure occurred in 15 patients, 2 being treatment-naive and 13 treatment-experienced. INSTI resistance changes were recognized in 12 patients: N155H (5), Q148H/R (3), Y143C/G (3) and R263K (1).

CONCLUSIONS

Combinations based on INSTIs are effective and safe treatment options for HIV-2-infected individuals. However, resistance mutations to INSTIs are selected frequently in failing patients, reducing the already limited treatment options.

Spatial Distortion of Vibration Modes via Magnetic Correlation of Impurities

Long wavelength vibrational modes in the ferromagnetic semiconductor Ga_{0.91}Mn_{0.09}As are investigated using time resolved x-ray diffraction. At room temperature, we measure oscillations in the x-ray diffraction intensity corresponding to coherent vibrational modes with well-defined wavelengths. When the correlation of magnetic impurities sets in, we observe the transition of the lattice into a disordered state that does not support coherent modes at large wavelengths. Our measurements point toward a magnetically induced broadening of long wavelength vibrational modes in momentum space and their quasilocalization in the real space. More specifically, long wavelength vibrational modes cannot be assigned to a single wavelength but rather should be represented as a superposition of plane waves with different wavelengths. Our findings have strong implications for the phonon-related processes, especially carrier-phonon and phonon-phonon scattering, which govern the electrical conductivity and thermal management of semiconductor-based devices.

Prevalence and distribution of hepatitis C virus genotypes in Spain during the 2000-2015 period (the GEHEP 005 study)

We report the largest study on the prevalence and distribution of HCV genotypes in Spain (2000-2015), and we relate them with clinical, epidemiological and virological factors. Patients from 29 hospitals in 10 autonomous communities (Andalusia, Aragon, Castilla-Leon, Catalonia, Galicia, Canary Islands, Madrid Community, Valencian Community, Murcia Region and Basque Country) have been studied. Annual distribution of HCV genotypes and subtypes, as well as gender, age, transmission route, HIV and/or HBV coinfection, and treatment details were recorded. We included 48595 chronically HCV-infected patients with the following characteristics: median age 51 years (IQR, 44-58), 67.9% male, 19.1% HIV-coinfected, 23.5% HBV-coinfected. Parenteral transmission route was the most frequent (58.7%). Genotype distribution was 66.9% GT1 (24.9% subtype 1a and 37.9% subtype 1b), 2.8% GT2, 17.3% GT3, 11.4% GT4 and 0.1% GT5 and 0.02% GT6. LiPA was the most widely HCV genotyping test used (52.4%). HCV subtype 1a and genotypes 3 and 4 were closely associated with male gender, parenteral route of infection and HIV and HBV coinfection; in contrast, subtype 1b and genotype 2 were associated with female gender, nonparenteral route and mono-infection. Age was related to genotype distribution, and different patterns of distribution and biodiversity index were observed between different geographical areas. Finally, we describe how treatment and changes in transmission routes may have affected HCV genotype prevalence and distribution patterns. We present the most recent data on molecular epidemiology of hepatitis C virus in Spain. This study confirms that genotype distributions vary with age, sex, HIV and HBV coinfection and within geographical areas and epidemiological groups.

Heterodyne x-ray diffuse scattering from coherent phonons

Here, we report Fourier-transform inelastic x-ray scattering measurements of photoexcited GaAs with embedded ErAs nanoparticles. We observe temporal oscillations in the x-ray scattering intensity, which we attribute to inelastic scattering from coherent acoustic phonons. Unlike in thermal equilibrium, where inelastic x-ray scattering is proportional to the phonon occupation, we show that the scattering is proportional to the phonon amplitude for coherent states. The wavevectors of the observed phonons extend beyond the excitation wavevector. The nanoparticles break the discrete translational symmetry of the lattice, enabling the generation of large wavevector coherent phonons. Elastic scattering of x-ray photons from the nanoparticles provides a reference for heterodyne mixing, yielding signals proportional to the phonon amplitude.

Healthy lifestyles programme in an acute psychiatric inpatient unit

Introduction

Mental health issues and illnesses are associated with poor self-care and unhealthy lifestyles that contribute to morbidity, mortality and overall decrease in quality of life when compared to the general population. Healthy lifestyle promotion is infrequently considered a priority in mental healthcare services, especially in acute psychiatric inpatient units.

Objectives

To present a healthy lifestyles promotion programme implemented in an acute psychiatric inpatient unit.

Aims

To reflect on how to design an adequate programme for patients with complex needs.

Methods

In a general psychiatric inpatient unit, a team of two psychologists and one psychiatrist, ventured to introduce weekly activities that included drawing, colouring, painting, crafts and games, that provided a context for patients and the team to sit down together or to gradually “drift” together and make possible conversations focusing on tobacco smoking, caffeine consumption, weight control, physical activity and health promoting activities.

Results

Instead of individual or group psychoeducation talk interventions, play and art strategies, in closer proximity with the patients, made it far easier to engage difficult patients and made psychoeducation possible and fun.

Conclusions

Patients with severe mental illness are frequently reluctant to engage in activities targeting healthy lifestyles, especially in acute psychiatric inpatient units, when insight and motivation for change may be low due to illness and consequences of illness. Play and art therapy interventions led by a team of mental healthcare professionals who participate directly with the patients, may be an innovative, more effective and enjoyable strategy.

Disclosure of interest

The authors have not supplied their declaration of competing interest.

Single Low-Dose Ionizing Radiation Induces Genotoxicity in Adult Zebrafish and its Non-Irradiated Progeny

This study investigated to what extent a single exposure to low doses of ionizing radiation can induce genotoxic damage in irradiated adult zebrafish (Danio rerio) and its non-irradiated F1 progeny. Four groups of adult zebrafish were irradiated with a single dose of X-rays at 0 (control), 100, 500 and 1000 mGy, respectively, and couples of each group were allowed to reproduce following irradiation. Blood of parental fish and whole-body offspring were analysed by the comet assay for detection of DNA damage. The level of DNA damage in irradiated parental fish increased in a radiation dose-dependent manner at day 1 post-irradiation, but returned to the control level thereafter. The level of DNA damage in the progeny was directly correlated with the parental irradiation dose. Results highlight the genotoxic risk of a single exposure to low-dose ionizing radiation in irradiated individuals and also in its non-irradiated progeny.

The origin of incipient ferroelectricity in lead telluride

The interactions between electrons and lattice vibrations are fundamental to materials behaviour. In the case of group IV–VI, V and related materials, these interactions are strong, and the materials exist near electronic and structural phase transitions. The prototypical example is PbTe whose incipient ferroelectric behaviour has been recently associated with large phonon anharmonicity and thermoelectricity. Here we show that it is primarily electron-phonon coupling involving electron states near the band edges that leads to the ferroelectric instability in PbTe. Using a combination of nonequilibrium lattice dynamics measurements and first principles calculations, we find that photoexcitation reduces the Peierls-like electronic instability and reinforces the paraelectric state. This weakens the long-range forces along the cubic direction tied to resonant bonding and low lattice thermal conductivity. Our results demonstrate how free-electron-laser-based ultrafast X-ray scattering can be utilized to shed light on the microscopic mechanisms that determine materials properties.

Group IV–VI materials often exist in a state near an electronic or structural phase transition. Here, the authors use ultrafast X-ray scattering to show that coupling of band-edge electrons and phonons causes the ferroelectric instability observed in lead telluride.

Smoking reduction/cessation and psychiatric patients: What about weight control?

Introduction

Smoking cessation has long been associated with weight gain and is one of the many reasons that smokers invoke for not giving up smoking. Many psychiatric medications are also associated with increased weight gain and metabolic syndrome. Unhealthy lifestyles reflect symptoms of illness with poor coping strategies and financial and social difficulties.

There are many reasons why smoking cessation may be viewed as much more difficult for psychiatric patients and weight gain is one of them.

Objective

To study how patients’ weight evolves during smoking reduction and cessation in a smoking reduction/cessation program in a psychiatric hospital.

Aims

To demystify weight gain as a significant problem in smoking reduction and cessation in this patient population.

Methods

Every patient entering the smoking reduction/cessation program is evaluated initially with regard to weight and BMI.

Patients’ weights are evaluated during the duration of the program for each patient as is smoking status.

Results

We are still collecting data at this time.

Conclusions

There are three groups of patient according to weight changes during the program: those who gain weight, those who maintain the same weight (± 1 kg) and those who lose weight.

Most patients who gain weight end up recuperating their initial weight or are able to lose weight later.

Some patients had weight control issues and their fear of gaining weight led them to overcompensate leading to weight loss.

We have included interventions on healthy lifestyles that have aided patients in controlling their weight.

Disclosure of interest

The authors have not supplied their declaration of competing interest.

Measurement of transient atomic displacements in thin films with picosecond and femtometer resolution

We report measurements of the transient structural response of weakly photo-excited thin films of BiFeO3, Pb(Zr,Ti)O3, and Bi and time-scales for interfacial thermal transport. Utilizing picosecond x-ray diffraction at a 1.28 MHz repetition rate with time resolution extending down to 15 ps, transient changes in the diffraction angle are recorded. These changes are associated with photo-induced lattice strains within nanolayer thin films, resolved at the part-per-million level, corresponding to a shift in the scattering angle three orders of magnitude smaller than the rocking curve width and changes in the interlayer lattice spacing of fractions of a femtometer. The combination of high brightness, repetition rate, and stability of the synchrotron, in conjunction with high time resolution, represents a novel means to probe atomic-scale, near-equilibrium dynamics.

Speed limit of the insulator-metal transition in magnetite

As the oldest known magnetic material, magnetite (Fe3O4) has fascinated mankind for millennia. As the first oxide in which a relationship between electrical conductivity and fluctuating/localized electronic order was shown, magnetite represents a model system for understanding correlated oxides in general. Nevertheless, the exact mechanism of the insulator-metal, or Verwey, transition has long remained inaccessible. Recently, three-Fe-site lattice distortions called trimerons were identified as the characteristic building blocks of the low-temperature insulating electronically ordered phase. Here we investigate the Verwey transition with pump-probe X-ray diffraction and optical reflectivity techniques, and show how trimerons become mobile across the insulator-metal transition. We find this to be a two-step process. After an initial 300 fs destruction of individual trimerons, phase separation occurs on a 1.5±0.2 ps timescale to yield residual insulating and metallic regions. This work establishes the speed limit for switching in future oxide electronics.

Real-time manifestation of strongly coupled spin and charge order parameters in stripe-ordered La(1.75)Sr(0.25)NiO(4) nickelate crystals using time-resolved resonant x-ray diffraction

We investigate the order parameter dynamics of the stripe-ordered nickelate, La(1.75)Sr(0.25)NiO(4), using time-resolved resonant x-ray diffraction. In spite of distinct spin and charge energy scales, the two order parameters' amplitude dynamics are found to be linked together due to strong coupling. Additionally, the vector nature of the spin sector introduces a longer reorientation time scale which is absent in the charge sector. These findings demonstrate that the correlation linking the symmetry-broken states does not unbind during the nonequilibrium process, and the time scales are not necessarily associated with the characteristic energy scales of individual degrees of freedom.

Temporal cross-correlation of x-ray free electron and optical lasers using soft x-ray pulse induced transient reflectivity

The recent development of x-ray free electron lasers providing coherent, femtosecond-long pulses of high brilliance and variable energy opens new areas of scientific research in a variety of disciplines such as physics, chemistry, and biology. Pump-probe experimental techniques which observe the temporal evolution of systems after optical or x-ray pulse excitation are one of the main experimental schemes currently in use for ultrafast studies. The key challenge in these experiments is to reliably achieve temporal and spatial overlap of the x-ray and optical pulses. Here we present measurements of the x-ray pulse induced transient change of optical reflectivity from a variety of materials covering the soft x-ray photon energy range from 500eV to 2000eV and outline the use of this technique to establish and characterize temporal synchronization of the optical-laser and FEL x-ray pulses.

Femtosecond dynamics of the collinear-to-spiral antiferromagnetic phase transition in CuO

We report on the ultrafast dynamics of magnetic order in a single crystal of CuO at a temperature of 207 K in response to strong optical excitation using femtosecond resonant x-ray diffraction. In the experiment, a femtosecond laser pulse induces a sudden, nonequilibrium increase in magnetic disorder. After a short delay ranging from 400 fs to 2 ps, we observe changes in the relative intensity of the magnetic ordering diffraction peaks that indicate a shift from a collinear commensurate phase to a spiral incommensurate phase. These results indicate that the ultimate speed for this antiferromagnetic reorientation transition in CuO is limited by the long-wavelength magnetic excitation connecting the two phases.

Imaging nonequilibrium atomic vibrations with x-ray diffuse scattering

We use picosecond x-ray diffuse scattering to image the nonequilibrium vibrations in the lattice following ultrafast laser excitation. We present images of nonequilibrium phonons in InP and InSb throughout the Brillouin zone which remain out of equilibrium up to nanoseconds. The results are analyzed using a Born model that helps identify the phonon branches contributing to the observed features in the time-resolved diffuse scattering. In InP this analysis shows a delayed increase in the transverse-acoustic (TA) phonon population along high-symmetry directions accompanied by a decrease in the longitudinal-acoustic phonons. In InSb the increase in TA phonon population is less directional.

Auger electron angular distribution of double core-hole states in the molecular reference frame

The Linac Coherent Light Source free electron laser is a source of high brightness x rays, 2×10(11) photons in a ∼5 fs pulse, that can be focused to produce double core vacancies through rapid sequential ionization. This enables double core vacancy Auger electron spectroscopy, an entirely new way to study femtosecond chemical dynamics with Auger electrons that probe the local valence structure of molecules near a specific atomic core. Using 1.1 keV photons for sequential x-ray ionization of impulsively aligned molecular nitrogen, we observed a rich single-site double core vacancy Auger electron spectrum near 413 eV, in good agreement with ab initio calculations, and we measured the corresponding Auger electron angle dependence in the molecular frame.

Time-resolved pump-probe experiments at the LCLS

The first time-resolved x-ray/optical pump-probe experiments at the SLAC Linac Coherent Light Source (LCLS) used a combination of feedback methods and post-analysis binning techniques to synchronize an ultrafast optical laser to the linac-based x-ray laser. Transient molecular nitrogen alignment revival features were resolved in time-dependent x-ray-induced fragmentation spectra. These alignment features were used to find the temporal overlap of the pump and probe pulses. The strong-field dissociation of x-ray generated quasi-bound molecular dications was used to establish the residual timing jitter. This analysis shows that the relative arrival time of the Ti:Sapphire laser and the x-ray pulses had a distribution with a standard deviation of approximately 120 fs. The largest contribution to the jitter noise spectrum was the locking of the laser oscillator to the reference RF of the accelerator, which suggests that simple technical improvements could reduce the jitter to better than 50 fs.

Tobacco Smoking and Motivation to Quit in Psychiatric Patients

Introduction:

Smoking is a major health risk in the population in general with significantly increased morbility/mortality with severe consequences on the quality of life and tremendous economic burden on society. It is well known that psychiatric patients have an even higher prevalence of smoking, of heavy smokers and of other risk factors that contribute to the same illnesses.

Non-smoking campaigns/smoking restrictions have flourished and it appears that more people are quitting or seriously contemplating the idea. When once, many non-smokers tolerated smokers, today the stigma associated with smoking is undeniable. Psychiatric patients, already greatly stigmatized, risk even becoming more so. Furthermore, smoking cessation programs and interventions frequently are not available, exclude many psychiatric patients and/or are ill-adapted to the special needs in this patient population.

Aim:

To establish the prevalence of smoking, quantity of tobacco smoked, other factors of dependence by psychiatric diagnosis in a portuguese psychiatric hospital.

Establish the motivation of these patients to seek help by professionals and motivation to quit.

Methods:

Application of questionnaires including Fagerstrom's Modified Questionnaire to patients under care by one team of a Psychaitric hospital in Lisbon, Portugal (CHPL - Sector A).

Discussion and conclusions:

The study is under way therefore, there are no valid conclusions yet.

Certainly it will be possible to confirm high levels of smoking tobacco in this patient population. Hopefully, we may also conclude that there is the desire to change smoking habits making cessation programs a needed and welcomed intervention in psychiatric settings.

Probing unfolded acoustic phonons with X rays

Ultrafast laser excitation of an InGaAs/InAlAs superlattice (SL) creates coherent folded acoustic phonons that subsequently leak into the bulk (InP) substrate. Upon transmission, the phonons become "unfolded" into bulk modes and acquire a wave vector much larger than that of the light. We show that time-resolved x-ray diffraction is sensitive to this large-wave vector excitation in the substrate. Comparison with dynamical diffraction simulations of propagating strain supports our interpretation.

Observation of surface-avoiding waves: a new class of extended states in periodic media

Coherent time-domain optical experiments on GaAs-AlAs superlattices reveal the existence of an unusually long-lived acoustic mode at approximately 0.6 THz which couples weakly to the environment by evading the sample boundaries. Classical as well as quantum states that steer clear of surfaces are generally shown to occur in the spectrum of periodic structures, for most boundary conditions. These surface-avoiding waves are associated with frequencies outside forbidden gaps and wave vectors in the vicinity of the center and edge of the Brillouin zone. Possible consequences for surface science and resonant-cavity applications are discussed.

Confinement of acoustical vibrations in a semiconductor planar phonon cavity

Extending the idea of optical microcavities to sound waves, we propose a phonon cavity consisting of two semiconductor superlattices enclosing a spacer layer. We show that acoustical phonons can be confined in such layered structures when the spacer thickness is an integer multiple of the acoustic half-wavelength at the center of one of the superlattice folded minigaps. We report Raman scattering experiments that, taking profit of an optical microcavity geometry, demonstrate unambiguously the observation of a phonon-cavity confined acoustical vibration in a GaAs/AlAs based structure. The experimental results compare precisely with photoelastic model calculations of the Raman spectra.

Standing optical phonons in finite semiconductor superlattices studied by resonant Raman scattering in a double microcavity

We report optical double resonant enhancement of Raman scattering in a new double microcavity geometry. The design allows almost backscattering geometries, providing easy access to the excitations' in-plane dispersion. The cavity is used to study the phonon spectra of a finite GaAs/AlAs superlattice. A new type of "standing optical vibration" is demonstrated involving the GaAs confined phonons with a standing wave envelope determined by the superlattice thickness. A strong dispersion of the first order standing wave mode is observed, as well as its anticrossing with higher order confined modes of the same symmetry.

[A retrospective study of patients with epidemic optic neuropathy in a health area]

The sample of 104 patients who were diagnosed optic epidemic neuropathy at the health area of the "Rampa" Polyclinic in 1993 was reviewed. 50 of them were studied again. Visual acuity as well as the sensitivity to contrast by the Pelli Robson's method were explored. Ishihara's color-vision test was applied and an ophthalmological examination including fundus of the eye was made. All this was done by a group of experts who were searching temporary papillary paleness or lost of the bundles of papillomacular fibres, which are the diagnostic elements of the disease even in those cases that recover vision. 21 (42%) of the 50 studied patients fulfilled the criteria established for these cases by the Ministry of Public Health concerning visual acuity and color vision to diagnose optic epidemic neuropathy, although only 14 (28%) were ratified as cases. The typical alterations of the fundus of the eye were described, confirming the diagnosis. Cases were classified according to the initial state of visual acuity and to evolution. 3 had had an affectation of the visual acuity of 0.1 or worse (severe), and only one patient had a mild affectation with 0.8 of vision. The rest ranged between 0.2 and 0.6. Only one patient had a serious sequela. The low percentage of cases ratified as optic epidemic neuropathy does not represent what happened in the whole country, but it may be considered as a pattern of what took place at those units with the same conditions during the peak of the epidemic.

Phase II of doxorubicin/taxol in metastatic breast cancer. Argentine Multicenter Taxol Group

PURPOSE

To assess the response rate, survival, and toxicity of Taxol (paclitaxel) as 1-h infusion plus doxorubicin as first-line treatment for patients with metastatic breast cancer (MBC).

PATIENTS AND METHODS

Seventy-six patients with untreated MBC were recruited. All of them had measurable disease and were evaluable for toxicity. Fifty-five percent of the patients had visceral involvement. The dose of doxorubicin was fixed at 50 mg/m2 as a short intravenous infusion, followed by 200 mg/m2 of Taxol as a 1-h intravenous infusion. Doxorubicin was administered during the first seven cycles, continuing with Taxol only up to a maximum of ten cycles.

RESULTS

Neutropenia was the most important toxicity: 30% grade 3 and 18% grade 4. Only 2 patients showed a decrease in the left ventricular ejection fraction (LVEF) which caused discontinuing the treatment. No clinical congestive heart failure (CHF) was observed. Seventy-four patients were eligible for response evaluation: 10 (14%) achieved complete response (CR) and 46 (62%) achieved partial response (PR). The mean duration of response was 13.47+/-1.35 months (95% confidence interval (CI): 10.82; 16.12) and the mean survival was 21.50+/-1.42 months (95% CI: 18.72; 24.29).

CONCLUSION

The overall response (OR) rate was 76%. No CHF was assessed and 2 patients stopped treatment due to LVEF decrease. Although doxorubicin 50 mg/m2 followed by Taxol 200 mg/m2 in 1-h intravenous infusion presents a toxicity profile which demands a close follow-up, it represents a convenient outpatient schedule with similar activity rate compared to longer Taxol infusions.

Congenital (?) Horners syndrome and ipsilateral headache

A 31-year-old woman had left-sided miosis, ptosis, and hypopigmented iris probably since birth. At 22, she developed intermittent headaches, always in the left frontotemporal region. These headaches lasted from 1 to 2 days and recurred every 1-2 months. Pain attacks were pressing-pulsatile in character, moderate in intensity, and frequently accompanied by nausea, vomiting, and moderate phono- and photophobia. Various treatment alternatives, such as conventional analgesics and ergotamine failed to improve the attacks. Pizotifen was partially effective. The results of pupillometry and evaporimetry studies were consistent with a 3rd neuron sympathetic hypofunction on the symptomatic side. Autonomic studies and clinical features were consistent with a congenital Horner's syndrome. Conceivably, a sympathetic hypofunction may play a role in the pathogenesis of such headache or in its lateralization. Indomethacin and sumatriptan both seemed to provide absolute pain relief. Some clinical features, the fact that the IHS criteria for migraine are fulfilled and that sumatriptan is efficient, demonstrate the similarity to migraine. The coexistence of strict unilaterality of pain and the probable, complete response to indomethacin indicate a similarity to hemicrania continua in its remitting form. Further information on the effect of sumatriptan in hemicrania continua will help clarify the position of this case vs. hemicrania continua. At this stage, it is probably not possible to classify this case properly.

Hemicrania continua. The first Spanish case: a case report

The case of a patient suffering from strictly unilateral continuous headache, absolutely responsive to indomethacin is reported. This is the first Hemicrania continua case to be documented in Spain. The tyramine test resulted in anisocoria with the smaller pupil on the symptomatic side. A second tyramine test after one week on 75 mg indomethacin per day failed to produce anisocoria. Treatment was reduced to 25 mg indomethacin per day, and this dose was sufficient to control the headache completely.

[Food taboos in the northern region of Brazil]

A study was carried out into alimentary taboos in two localities (São Félix and Murumuru) in the county of Marabá, State of Pará, Brazil. Ninety families were studied in São Félix and thirty-five in Murumuru. As regards the feeding taboos found, the most frequent was that prohibiting the simultaneous ingestion of milk and various types of fruit, including especially mango, orange, cashew and pineapple. The ingestion of eggs with fruit was also considered harmful as well as the eating of mammalian flesh at the same time as fish. Restrictions based on taboos were more frequent during breast feeding than during pregnancy, especially those regarding game flesh and fish that abound in the region under study. The most frequently mentioned reasons for the restrictions were: "the combination causes harm", "the combination kills", "the combination causes congestion" and "it causes vomiting".